Electronic rotary hammer

ABSTRACT

An electronic rotary hammer which utilizes a moving magnetic field to energize a rotary hammer having a cylindrical member formed with an internal groove in which a hammer member is supported so as to move longitudinally of the hammer in response to variations of the magnetic field. The hammer rotates as well as being moved upwardly and downwardly by a distributor which controls the application of a magnetic field so as to drive the hammer member.

United States Patent 1 Michaelson June 26, 1973 ELECTRONIC ROTARY HAMMER [75] Inventor: Dennis M. Michaelson, Chicago, Ill.

[73] Assignee: Pan-Technic, Inc., Chicago, Ill.

[22] Filed: Oct. 20, 1971 [21] Appl. No.: 190,930

[52] US. Cl 318/122, 310/23, 310/35 [51] Int. Cl. H02k 33/00 [58] Field of Search 310/20, 23, 24, 30,

3l0/34,35,l2,14,31,17;3l8/121,122,123, 134, 35,115, 282,114

[56] References Cited UNITED STATES PATENTS 494,053 3/1893 Birkin 318/122 2,110,033 3/1938 Bostick 310/23 X 3,140,412 7/1964 Godwin 310/23 942,396 12/1909 Lincoln... 310/31 X 1,276,804 8/1918 Painter 310/17 r mer xqm kpqn venfi P s?! Attorney-Carlton Hill, .1. Arthur Gross et a1.

[57] ABSTRACT An electronic rotary hammer which utilizes a moving magnetic field to energize a rotary hammer having a cylindrical member formed with an internal groove in which a hammer member is supported so as to move longitudinally of the hammer in response to variations of the magnetic field. The hammer rotates as well as being moved upwardly and downwardly by a distributor which controls the application of a magnetic field so as to drive the hammer member.

4 Claims, 1 Drawing Figure ELECTRONIC ROTARY HAMMER DESCRIPTION OF THE PRIOR ART Air hammers driven by compressed air are known as well as those which operate on the diesel principle wherein a piston moves upwardly and downwardly in a cylinder into which fuel is injected.

SUMMARY OF THE INVENTION The present invention relates to an electronic rotary hammer comprising a cylindrical body member formed with a handle and in which is mounted a movable hammer element which is guided by grooves formed in the cylindrical member. A plurality of magnetic coils are mounted about the cylindrical member so as to sequentially drive the hammer member upwardly and downwardly relative to the cylindrical member into grooves so that the hammer member rotates as well as moves up and down in the cylindrical member. A distribution system is connected to the magnetic field producing means of the hammer such that the magnetic field moves upwardly and downwardly relative to the cylindrical member thus driving the hammer member longitudinally in both directions in the cylindrical member. A field producing means is provided which senses when the hammer nears the end of travel in the cylindrical member so as to reverse the direction of movement of the field relative to the cylindrical member and thus impel the hammer member in the opposite direction.

Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof taken in conjunction with the accompanting drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concept of the disclosure and in which:

BRIEF DESCRIPTION OF THE DRAWING The FIGURE illustrates the novel electronic rotary hammer of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The FIGURE illustrates the electronic rotary hammer of this invention which comprises a hollow cylindrical member designated generally as 47 in which a hammer member 53 is mounted. The hammer member 53 is formed with guide lugs 56 and 57 which are received in a groove 58 formed in the inner wall of the cylindrical member 47 so as to rotate the hammer member 53 as it passes longitudinally up and down the cylindrical member 47. The end 51 of the cylindrical member is formed with an opening 52 through which the cutting point 59 of the hammer member 53 extends. The lugs 56 and 57 are mounted on a discshaped body portion of the hammer member 53 as shown.

Reversing linkage 61 extends through an opening formed in the wall 51 of the cylindrical member 47 and controls a reversing switch of a power distributing system.

A spring 67 is mounted at the other end of the cylindrical member 47 so as to engage the hammer member 53 when it moves to the up position relative to the FIG- URE. A reversing linkage 66 passes through the end wall 63 of the cylindrical member and controls the distribution system for the magnetic field generating means. A handle 49 is connected to the cylindrical member 47 as shown.

The cylindrical wall 48 of the cylindrical member has mounted a plurality of coils 41-46 which are spaced longitudinally about the cylindrical member 47. The first leads of the coils 41-46 are designated as 71-76 and are connected to a common lead 69 which is connected to a terminal 22 of reversing switch S2. The other side of coil 41 is connected by lead 35 to a wiper contact 29 engageable with distributing brush 28. The other side of coil 42 is connected by lead 36 to a wiper segment 30 engageable by the brush 28. The other side of coil 43 is connected by lead 37 to wiper segment 31 engageable by the brush 28. The other side of coil 44 is connected by lead 38 to a segment 32 engageable by brush 28. The other side of coil 45 is connected by lead 39 to a segment 33 engageable by brush 28 and the other side of coil 46 is connected by lead 40 to a segment 34 engageable by brush 28. The brush 28 is connected by lead 27 to terminal 21 of the reversing switch S2. A battery E has its positive terminal connected by lead 13 to first contact 16 of the reversing switch S2 and the positive terminal is also connected to terminal 19 of the reversing switch. The negative terminal of the battery E is connected by lead 14 to terminals 17 and 18 of the reversing switch. A reversible motor 10 has one lead connected to terminal 22 of the reversing switch and the other lead 11 is connected to an On-Off switch S1 to terminal 21 of the reversing switch S2. Mechanical linkage 26 is connected to the reversing linkage 61 to move the reversing contact 23 of the reversing switch S2. The linkage 24 is coupled to the reversing linkage 66 and is connected to the movable contact 23 of the reversing switch S2. The output shaft of the motor is designated as 81 and is connected to the brush 28.

In operation the switch S1 is closed and the switch S2 is closed so that contact 21 engages contact 16 applying a positive voltage to lead 27 and the rotary brush 28. Simultaneously contact 22 is connected to the negative terminal of the battery E through the contact 17. Energizing power is applied to the motor 10 through leads 11 and 12 and it commences to drive the brush 28 counterclockwise relative to the FIGURE. When the brush 28 engages the wiper contact 29, positive voltage is connected to lead 35 and to the winding 41 and the negative terminal of the battery is connected by lead 69 to the other side of the winding 41. This causes a magnetic field to be produced by winding 41 which moves the hammer member 53 upward relative to the FIGURE. The hammer member thus starts to move upwardly as the motor 10 continues to rotate. The brush 28 then engages the wiper contact 30 after disengaging the contact 29 and positive voltage is applied to winding 42 through lead 36 and common lead 69. This causes a magnetic field to be produced in winding 42 which drives the hammer member 53 upward relative to the FIGURE. The brush 28 continues to move next engaging contact 31 which energizes winding 43 moving the hammer member 53 further upwardly in the tube of the cylindrical member 47 and sequentially as the brush engages contacts 32, 33 and 34 the windings 44, 45 and 46, respectively, will be energized, thus impelling the hammer member 53 to the upper end of the cylindrical member 47 where it will engage the spring 67 which decelerates it and simultaneously engages the reversing linkage 66 which moves the movable contact 23 of the reversing switch S2 from engagement with contacts 16 and 17, respectively, into engagement with contacts 18 and 19, respectively, thus reversing the polarity of the voltage applied to motor and simultaneously reversing the polarity to the brush 28 and the common lead 69. The motor will stop and will reverse direction and commence to rotate clockwise relative to the drawing such that the wiper contact engages wiper contact 34 applying a negative voltage to lead 40 and a positive voltage to lead 69, thus energizing winding 46 so as to drive the hammer member 53 downwardly relative to the FIGURE. The brush 28 will then engage the wiper contact 33 energizing winding 45 causing the hammer member 53 to be driven downwardly in the cylindrical member 48. The brush will continue to sequentially energize the windings 44-41 driving the hammer member downwardly so that the point 59 extends from the end wall 51 of the hammer member and engages the material being broken or cut.

When the hammer member 53 nears the end wall 51 it engages a spring 62 and also engages the reversing linkage 61 which moves through the linkage 26, the reversing contact 23 of reversing switch S2 so that it moves to engage the contacts 16 and 17, respectively. Thus again reversing the polarity of the voltage applied to the motor 10 causing it to reverse direction so that it drives brush 28 in the counterclockwise direction and the sequence is repeated.

It is to be realized that the walls 48 of the cylindrical member are of non-magnetic material so that the magnetic field is closely coupled to the hammer member 53. The point 59 of the hammer member might comprise a carbide bit, for example.

It is to be realized that although a particular ditribution system is shown comprising the motor 10, that it is possible to provide a high frequency generator with electronic control so as to sequentially energize the driving coils 41-46 so as to operate the rotary hammer. Instead of a mechanical linkage such as shown in the drawing, electrical switches can be used which are to be directly actuated by the hammer member 53 as it moves to opposite ends of the cylindrical member 47.

The output power of the hammer depends upon the length of the barrel tube, the number of coils or windings surrounding the tube and the number of turns in each coil. The speed of applying the field up and down the tube also controls the power applied to the hammer member 53.

Many advantages of the design over conventional devices exist. For example, the tool may be of a very light weight construction, and, may operate very quietly. It has few moving parts and thus would be subject to a long and useful life. The device may be operated at variable speeds by providing a variable speed control 82 in the motor circuit such that the ditribution of the energy to the coils varies as the speed of the motor.

It is to be realized, of course, that with the electrical system of the present invention no air pollution would occur as presently occurs with diesel actuated or gasoline engine actuated rotary hammers. It should also be realized, of course, that the generator may be simultaneously used with several different hammers. Noise pollution which presently occurs with air hammers would be substantially eliminated in that the present invention operates in a quiet manner.

It is seen that this invention provides a simple and inexpensive rotary hammer in which the energy imparted to the bit not only is imparted longitudinally to the material being broken but also a rotary torque is applied by the bit due to the rotation of the hammer member 53 caused by the helical groove 58 which causes the hammer member 53 to rotate.

it is to be realized that any type of power supply could be used instead of the battery E. For example, a stationary power means could be used.

Although the invention has been described with preferred embodiments it is not to be so limited as changes and modifications may be made therein which are within the full intent and scope as defined by the appended claims.

I claim:

I. A magnetic hammer comprising:

a hollow body member formed with an opening at one end thereof;

a movable hammer member of magnetic material mounted in said hollow body member and formed with a tool portion extendable through said opening of said body member;

magnetic drive means comprising a plurality of magnetic coils mounted about said body member and spaced longitudinally along said body member;

a power source;

distributing means connected between said power source and said magnetic drive means to drive said movable hammer means in both directions longitudinally of said body member and such that said tool portion of said hammer means is driven out through said opening of said body member;

means for imparting rotary motion in a first direction to said hammer member as it moves relative to said body member in one direction and imparting rotary motion in a second direction as it moves relative to said body member in the opposite direction, and comprising a helical groove formed in said body member and a guide formed on said hammer member and receivable in said groove; and

a pair of magnetic field reversing means forming a part of said distributing means mounted at opposite ends of said body member and engageable by said hammer member to reverse the magnetic field in said body member.

2. A magnetic hammer according to claim 1 wherein said distributing means supplies power from said power source to said plurality of magnetic coils on a time sequential basis so as to drive said movable magnetic hammer longitudinally of said body member.

3. A magnetic hammer according to claim 2 wherein said distributing means includes a plurality of wiper contacts and brush contact engageable with said wiper contacts, a drive means connected to said brush contact and said wiper contacts connected to said plurality of magnetic coils.

4. A magnetic hammer according to claim 3 wherein said magnetic field reversing means are connected in circuit with said drive means, said power source, said brush contact and said wiper contacts to effect a reversal in direction of said hammer member. 

1. A magnetic hammer comprising: a hollow body member formed with an opening at one end thereof; a movable hammer member of magnetic material mounted in said hollow body member and formed with a tool portion extendable through said opening of said body member; magnetic drive means comprising a plurality of magnetic coils mounted about said body member and spacEd longitudinally along said body member; a power source; distributing means connected between said power source and said magnetic drive means to drive said movable hammer means in both directions longitudinally of said body member and such that said tool portion of said hammer means is driven out through said opening of said body member; means for imparting rotary motion in a first direction to said hammer member as it moves relative to said body member in one direction and imparting rotary motion in a second direction as it moves relative to said body member in the opposite direction, and comprising a helical groove formed in said body member and a guide formed on said hammer member and receivable in said groove; and a pair of magnetic field reversing means forming a part of said distributing means mounted at opposite ends of said body member and engageable by said hammer member to reverse the magnetic field in said body member.
 2. A magnetic hammer according to claim 1 wherein said distributing means supplies power from said power source to said plurality of magnetic coils on a time sequential basis so as to drive said movable magnetic hammer longitudinally of said body member.
 3. A magnetic hammer according to claim 2 wherein said distributing means includes a plurality of wiper contacts and brush contact engageable with said wiper contacts, a drive means connected to said brush contact and said wiper contacts connected to said plurality of magnetic coils.
 4. A magnetic hammer according to claim 3 wherein said magnetic field reversing means are connected in circuit with said drive means, said power source, said brush contact and said wiper contacts to effect a reversal in direction of said hammer member. 